Two people familiar with the case told The Associated Press that Pettitte was in Washington last week to meet with prosecutors.
Pettitte could be a crucial witness for any case against Clemens. The two trained together for years.
Pettitte has acknowledged taking human growth hormone and told congressional investigators that Clemens informed him nearly a decade ago that he used HGH.
Prosecutors are weighing whether to bring perjury charges against Clemens for denying under oath to Congress that he took performance-enhancing substances.
Asked about his meeting with prosecutors, Pettitte said, "I can't talk to you about that."
MARLINS: Manager Fredi Gonzalez received a contract extension through the 2011 season.
Before managing the Marlins, the 45-year-old Gonzalez spent five seasons with the Braves, including four as their third base coach.
PIRATES: Outfielder Nate McLouth reached an agreement on a $15.75 million, three-year contract that includes a team option for 2012.
McLouth hit .276 last season with 26 home runs and 94 RBI. He was on the NL All-Star team and won a Gold Glove in center field.
DODGERS: Agreed to a $3.1 million, one-year deal with outfielder Andre Ethier, who batted .305 with 20 homers and 77 RBI last year.
REDS: Edwin Encarnacion has agreed to a two-year contract that will pay the third baseman at least $7.6 million through the 2010 season. Encarnacion batted .251 last season with 26 home runs and 68 RBI.
CARDINALS: Third baseman Troy Glaus can't throw or hit after having surgery for a muscle tear in his right shoulder Jan. 21. He could return sometime late in April.